Background. Xanthogranulomatous pyelonephritis is characterized by the inflammatory destruction of the renal parenchyma and intensive renal fibrosis. It is named because of its pathological appearance; that of its granulomatous inflammatory process with lipid-laden macrophages, which appear yellow, hence `xantho` which is Greek for yellow. Xanthogranulomatous pyelonephritis is predominantly a disease of adults. In children it is diagnosed sporadically and is extremely rare in infants. The age of onset varies (21 days to 16 years), although 60-75% of cases have been diagnosed before 5 years of age. Recurrent urinary tract infections, obstructive nephropathy caused by renal calculus, malnutrition, abnormal lipid metabolism, altered immunologic response, lymphatic blockage, congenital urinary anomalies have been implicated in the etiology of xanthogranulomatous pyelonephritis in children.

Case. We report an unusual case of xanthogranulomatous pyelonephritis in a 5-year-old girl and discuss its clinical features, histopathological findings and treatment. In this article, we also emphasized the importance of diagnostic imaging in urinary tract infections which enabled us not to miss the underlying kidney stone disease.

Conclusion. Nephrolithiasis may lead to very serious conditions such as xanthogranulomatous pyelonephritis. This condition can be easily diagnosed by ultrasound, but if not detected, it can lead to complete loss of renal function as in the case.

Keywords: Xantogranulomatous pyelonephritis, kidney stones, nephrolithiasis